Ios XrOperating system · Cisco
CVE-2015-4285
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThe Local Packet Transport Services (LPTS) implementation in Cisco IOS XR 5.1.2, 5.1.3, 5.2.1, and 5.2.2 on ASR9k devices makes incorrect decisions about the opening of TCP and UDP ports during the processing of flow base entries, which allows remote attackers to cause a denial of service (resource consumption) by sending traffic to these ports continuously, aka Bug ID CSCur88273.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA logic flaw in Cisco IOS XR's Local Packet Transport Services (LPTS) on ASR9k devices causes incorrect decisions when processing flow base entries, resulting in improper handling of TCP and UDP port opening. Remote attackers can continuously send traffic to specific ports to exhaust device resources, causing denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Ios XrOperating system
= 5.1.2= 5.1.3= 5.2.1= 5.2.2CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify the hardware platformUse 'show platform' or check the device model to confirm it is an ASR9k router. This vulnerability only affects ASR9k devices running Cisco IOS XR.Affected if The device is not an ASR9k (ASR 9000 Series), then it is not affected by this CVE.
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Determine the IOS XR versionExecute 'show version' or 'show install active' to retrieve the running Cisco IOS XR version number.Affected if The installed version is exactly 5.1.2, 5.1.3, 5.2.1, or 5.2.2 - compare your version against these four affected versions.
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Confirm LPTS is activeUse the appropriate command to display Local Packet Transport Services (LPTS) status and flow base entries, such as 'show lpts' or 'show lpts flow' if available on your system.Affected if LPTS flow base processing is enabled and actively handling TCP/UDP port entries - this is required for the flaw to be exploitable.
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Check for abnormal port behaviorMonitor LPTS flow table entries for unexpected or rapidly changing TCP/UDP port openings that were not configured by the administrator.Affected if There is evidence of unauthorized or unexpected port entries being created in the flow base, which may indicate exploitation attempts.
If the device is an ASR9k running IOS XR version 5.1.2, 5.1.3, 5.2.1, or 5.2.2 with LPTS flow processing active, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade Cisco IOS XR to a version beyond 5.2.2 that contains the fix for CSCur88273, or implement traffic filtering/ACLs to limit the specific attack vectors until upgrade is possible.
Fix this in Ios Xr
Scoped from the published advisory
- Consultation6.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,368.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-4285 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-4285 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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